Fluid-cooled panel for furnace hood

ABSTRACT

A fluid-cooled panel especially useful to form a hood for conducting hot gases released from a basic oxygen furnace during the oxygen blowing periods. The panel is comprised of tubular fluid passageways alternating with solid panel portions, the latter being thinner and narrower than the passageways and offset to one side of the midplane of the panel. Headers conduct fluid to and from the passageways. In use, the panel is oriented with the solid panel portions offset from the midplane toward the cold side of the panel.

United States Patent [191 Highberger F LUID-COOLED PANEL FOR FURNACE HOOD [75] Inventor: Grant H. ll-Iighberger, Lyndhurst,

Ohio

[73] Assignee: Republic Steel Corporation,

Cleveland, Ohio [22] Filed: July 11, 1973 [21] Appl. No.: 378,095

Related [1.8. Application Data [63] Continuation of Ser. No. 160,718, July 8, 1971,

abandoned.

[52] US. Cl 266/16, 122/7 A, 165/171 [51] Int. Cl. C21c 5/40 [58] Field of Search 122/7 R, 7 A, 6 A, 235 A, 122/235 C; 165/168, 169, 171; 266/15, 16, 19, 31, 32, 35, 36 P; 29/157.3 D

[56] References Cited UNITED STATES PATENTS 2,271,437 l/1942 Lewis 165/169 3,120,869 2/1964 Carpenter.... 122/6 A 3,323,495 6/1967 Blaskowski 1 122/7 A 3.425.113 2/1969 Ward 29/1573 D 1 Dec. 17, 1974 FOREIGN PATENTS OR APPLICATIONS 1,110,439 4/1968 Great Britain a. 122/60 A 907,912 10/1962 Great Britain 165/16X 1,103,292 11/1955 France 266/32 276,013 11/1927 Great Britain .1 165/168 OTHER PUBLICATIONS Publication: Babcock & Wilcox brochure; 1962; The New B and W Oxygen Furnace Hood".

Primary Examiner-Gerald A. Dost Attorney, Agent, or FirmWatts, Hoffman, Fisher & Heinke Co.

[ 5 7] ABSTRACT A fluid-cooled panel especially useful to form a hood for conducting hot gases released from a basic oxygen furnace during the oxygen blowing periods. The panel is comprised of tubular fluid passageways alternating with solid panel portions, the latter being thinner and narrower than the passageways and offset to one side of the midplane of the panel. Headers conduct fluid to and from the passageways. In use, the panel is oriented with the solid panel portions offset from the midplane toward the cold side of the panel.

4 Claims, 5 Drawing Figures Pix-TENTH; SEC 1 7 1974 SNEH 10F 2 I INVENTOR. GPA VT H. HIGH/BERGER B W, WWW, 9m M ATTOENEYS.

PATENTEL; LEE] 7 I974 SHEET 2 OF 2 Fig. 4

- INVENTOR. GPAA/T H. H/GF/BEPGEP mm ATTOENEYS 1 FLUID-COOLED PANEL FOR FURNACE HOOD CROSS REFERENCE TO RELATED APPLICATION This is a continuation of application Ser. No. 160,718, filed July 8, 1971 and now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an internally fluid-cooled panel and especially to a panel of that type for use in a hood for a basic oxygen furnace.

2. Prior Art Water-cooled hoods for the purpose-of collecting and conducting hot gases from a basic oxygen furnace are shown in U.S. Pat. No. 3,445,101 and are described in an article entitled Operating Performance and improvements to Membrane Hoods for Basic Oxygen Furnaces, by T. B. Hurst, Iron and Steel Engineer, December 1966, pages 101 to 107. As disclosed by the above references, collecting hoods are used with basic oxygen furnaces to collect hot gases released during the oxygen blowing periods. These hoods are made of a number of large panels, each of which may be about 2% to 4 feet wide by to feet long, arranged adjacent one another to form a conduit or hood-like affair that is supported directly above a basic oxygen furnace.

As shown by the references cited above, two typical types of construction include a welded membrane, formed of tubular'passageways joined by a webbing, and a hollow panel construction with longitudinal depressions providing rigidity and defining channels. In addition, longitudinal ribs or the like can be provided on panels to provide additional structural rigidity in an attempt to .avoid thermal warping that occurs when heat is applied unequally to opposite sides of the panels.

During the blowing period of a refining cycle, which blowing period may last about 18 to- 24 minutes, gases at extremely high temperatures, on the order of 3,200 to 3,400 Fahrenheit, are released. During other portions of the refining cycle, the temperature to which the hood is subjected will be substantially lower, and approximately every 40 to minutes, when a heat is tapped, the temperature of the gases flowing through the hood of thefurnace drops to ambient temperature. As a result, the hood panels are subjected not only to high temperatures during use, but also to severe fluctuations in temperature.

To withstand the high temperatures of operation, the panels forming the hood are water-cooled, being either hollow or formed of or incorporating tubes for the circulation of water. Cooling of the panels serves the additional function of reducing the temperature of the collected gases so that they can beconveyed to a suitable system for dust and fume removal. Notwithstanding the cooling of the panels, the high temperature on the inside of the hood and the fluctuations of the temperatures impose substantial stresses on the panels that result in temporary and permanent warping. Temporary warping results from the presence of a temperature differential on opposite sides of the panel and causes the panel to bow convexly toward the heat. This warping occurs when hot gases flow through the hood, as during the oxygen blowing period, and may not in itself be so severe as to impair the functioning of the hood, especially if the panel is structurally reinforced. However, a certain amount of permanent deformation results from the bowing and the high temperatures, causing a change in the initial configuration, specifically, a permanent bow in the opposite direction from that temporarily caused by the temperature differential. This permanent change in configuration is cumulative over a series of heating and cooling cycles, as the furnace and hood are used. This cumulative distortion eventually reaches a magnitude that necessitates replacement of the panel, at substantial cost. In summary, then, notwithstanding panel cooling and the inherent rigidity of conventional panels, practice has shown that basic oxygen furnace hood panels become sufficiently and permanently warped during use so that frequent replacement is required. Attempts to prevent warping by imparting additional strength through ribs or other reinforcements has not provided a completely satisfactory solution to the problem, and increases the cost and weight of the panels.

SUMMARY OF THE INVENTION nace has been provided that promotes thermal expansion of generally similar or comparable magnitude on both sides of the panel midplane when heat is applied to one side and that tends to equalize or promote equalization of temperatures on opposite faces of the panel. This in turn reduces or eliminates the unequal stresses that typically are created on opposite faces or sides of a hood panel, which tend to temporarily warp, i.e., bow, the panel. As a consequence, the stress relaxation that occurs in the panel faces due to the high temperatures is generally comparable on both sides of the panel so that permanent warp is also reduced.

Reduction in both temporary and permanent bowing or warping is accomplished by constructing the panel of a plurality of tubular fluid passageways and intermediate solid or dry, panel portions that are thinner than the passageways and are offset to one side of a midplane through the thickness of the panel. Preferably, the solid portions lie in the plane of one face of the panel. The side to which the solid portions are offset is adapted to face outwardly of the hood and forms the cold side of the panel. With this construction, the outwardly facing surface will, in use, include portions, i.e., the intermediate solid or dry panel portions, that are substantially as hot as the inwardly facing surface of the hood. Heat flow from these portions along the outer surface of the panel raises the temperature of the outwardly facing surface, including those portions thereof that form the fluid passageways.

Preferably, the solid or dry portions and the fluid passageways extend longitudinally of the panel and the solid portions are located, with respect to the thickness of the panel, as far from the midplane as any portion of the passageways. With that arrangement, when the panel is oriented so the solid panel portions are located on the cold side of the panel midplane, i.e., away from the source of heat, the expansion of the intermediate solid portions tends to counteract the distortion that would otherwise be imparted to the panel by the expansion of panel parts that face the source of heat and are spaced from the midplane of the panel toward the hot side.

The preferred construction of the panel has a substantially flat outside surface, with the passageways extending essentially to one side thereof, so that one side (the hot side) has a corrugated appearance. Advantageously, the panel can be constructed from a corrugated sheet member with the peaks of the corrugations on one side being bridged, i.e., connected, by strips extending longitudinally of the corrugations and welded along adjacent peaks to form conduits or passageways for the flow of cooling liquid. This efficiently establishes the desired structure as described above and at the same time locates all welded seams of the panel on the outside surface to facilitate repair during use. Headers are provided at opposite ends of the panels, in

' communication with the passageways, to supply and exhaust fluid.

Panels of the above construction are supported in use in a conventional manner or in any suitable way, to form a hood for conducting gases from a basic oxygen furnace. The header of each panel is connected to that of another or to a manifold through which fluid is supplied or exhausted, so that a flow of fluid is provided throughout the panels forming a hood.

A principal object of this invention is to provide an improved, fluid-cooled, panel, suitable for use in a basic oxygen furnace hood, that resists thermal warping and the permanent deformation that results when one panel side is repeatedly subjected to high temperatures.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a panel embodying the present invention, adapted for use in a basic oxygen furnace hood, illustrating the outwardly facing surface or cold side of the panel;

FIG. 2 is a side elevational view of the panel of FIG.

- FIG. 3 is a transverse sectional view taken along the line 3-3 in FIG. 1;

FIG. 4 is a partial longitudinal sectional view taken along the line 4-4 in FIG. 1; and

FIG. 5 is a diagrammatic perspective view of a basic oxygen furnace hood, illustrating the manner in which panels of the type shown in FIG. 1 to 4 are assembled to form a hood for a furnace.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT I A panel 10, illustrative of a preferred embodiment of this invention, is shown in FIGS. 1 to 4. The manner in t which a plurality of panels are assembled to form a hood 12 for a basic oxygen furnace BOF, is illustrated in FIG. 5. While the panel 10 shown is rectangular, it should be appreciated that other shapes are utilized, to provide the necessary taper or other configuration of the hood, including openings and the like. To this end, the longitudinal side edges may converge or be configured to form a part of a opening, such as the opening 14 in the hood 12 for an oxygen lance. The panels 10 are typically large, approximately 2% to 4 feet wide by 15 to feet long and 1 to 3 inches in thicknessl Each panel is comprised of a plurality of longitudinal, parallel, passageways 16 through which cooling water is circulated. Opposite ends of the passageways connect to manifolds 18, 19 that form a part of the panel, one manifold having one or more inlet conduits 20 and the other having one or more outlets 21. The manner in which the passageways communicate with the manifolds is shown in FIG. 4. Panels 10 are arranged sideby-side and end-by-end to form the hood 12. In the embodiment shown, the hood 12 has a generally rectangular cross-sectional configuration, but other shapes are used as well. The panels 10 are supported in side-byside relationship on frame assemblies 24. Cross-bars 26 on one face of each panel 10 engage a frame assembly for support in a manner known in the art. The frame as semblies 24 are of known construction, fabricated from pipe sections, and one or more may serve as a conduit for introducing fluid to the inlet conduits 20 of the manifolds of panels at the lower end of the hood 12 and for receiving fluid exhausted from conduits 21 of panels adjacent the upper end of the hood. Continuous flow is typically provided through successive longitudinally aligned panels, by hose connections at adjacent inlet and outlet manifolds at locations between opposite ends of the hood.

While the manifolds 18, 19 at opposite ends of the panel 10 are parallel, it will be appreciated that where non-parallel longitudinal panel sides are required for certain portions of the hood, e.g., to provide a flared portion, all of the passageways 16 will not extend the complete distance between opposite parallel ends of the panel. Accordingly, the manifold at the narrower end of the panel may also extend along the longitudinal side edge of the panel that is at an angle to the passageways 16 so that all passageways 16 communicate at opposite ends with manifolds. Similarly, a manifold about the perimeter of an opening or curved portion of a panel will assure a flow of fluid through all passageways 16.

As best shown in FIG. 3, the parallel passageways 16 are tubular, extend the length of the panel 10, and are spaced in the direction across the panel width by solid metal portions or dry portions 30. The dry portions are substantially thinner than the passageways so that at least one surface of the panel has a corrugated appearance. The midplane through the thickness of the corrugated or passageway portion of the panel 10 is indicated in FIG. 3 at MP. The opposite faces of the panel are indicated by reference characters CF and HF.

The face designated CF is adapted in use to form the outside surface of the hood 12 and is therefore a cold face. The surface designated HF is adapted in use to fomi the inside surface of the hood 12 and is therefore a hot face. The solid metal portions 30 between the passageways 16 form a part of both the hot face and the cold face. In the preferred construction, the solid metal portions 30 are located as far from the midplane MP as any portion of the conduits 16, as shown in FIG. 3. As

a result, cold face side CF is generally planar.

In the embodiment shown, the panel 10 is formed from a generally corrugated, rectangular-shaped, sheet 32 and a plurality of separate strips 34 that are secured to the sheet by welds W at opposite edges along the corrugations, each strip spanning the distance between two adjacent ridges of the sheet 32. While the exact configuration of the sheet 32 can be varied while maintaining the general relationships specified, a specific configuration that is particularly satisfactory is illustrated in FIG. 3. As shown, the corrugated sheet 32, is in part formed of the solid or dry metal portions 30, which are flat and lie in a common plane, and in part by other flat sections 36 in a common plane parallel to but spaced from the plane in which the portions 30 lie. The portions 30 and 36 are connected by sheet portions 38, 39, which are also flat, face each other, and converge in the direction from the panel of the portions 36 toward the portions 30. The portions 30, 36, 38, 39 of the sheet 32 are proportioned so that the distance between successive solid metal portions 30 is greater than the width of the portions 30. The strips 34 are of a width such that they fit between successive solid metal portions 30 and contact the connecting portions 38 and 39 where each adjoins a portion 30, and the strips are substantially in the plane of the portions 30. The strips are welded along each longitudinal edge and, with the solid metal portions 30, form a substantially flat face of the panel 10. The strips also form, along with the flat sections 36 and connecting portions 38, 39, the longitudinal passageways 16.

In use, heat is applied to the corrugated or hot face side HF of the panel 10. The solid metal portions or -dry portions 30, essentially common to both the hot face and cold face sides of the panel, will become the hottest portions of the panel because they are exposed to direct heat on the hot face side without being directly contacted by a flow of cooling fluid, as are the portions 36, 38, 39. Linear expansion of these portions 30 longitudinally of the panel will apply a force tending to counteract the normal tendency of the hot face side to how the panel to an outwardly concave shape, because the portions 30 are displaced to the cold face side of the panel midplane. From a practical standpoint, it is not necessary to provide completely balanced forces, since some distortion is acceptable and the inherent structural rigidity due to the corrugated shape of the sheet 32 will resist deformation from moderate stresses. The relative area of the dry portions 30 compared to the remaining area and the structural rigidity of the panel will determine the actual extent of distortion.

The present construction has the important advantage of distributing the heat from the hot face side effectively to the cold face side. By virtue of the straight path from the hottest portions 30 to the longitudinal centerline of the adjacent strips 34, which are the coldest portions of the panel, the rate at which heat is distributed over the cold face side is maximized.

A further advantage of the preferred construction shown in FIG. 3, is that the welded seams between the strips 34 and the corrugated sheet 32 are all located on the external face or cold face of the hood panel. As a result, should there be a failure in a weld during use, the panel can be repaired without disturbing the hood.

During use of the hood l2, slag particles, dust, and the like tend to accumulate on the inside or hot face surface of the panels 10. The arrangement by which the connecting portions 38, 39 of each panel converge toward the cold face side avoids to a great extent excessive accumulation of these substances by making the grooves between adjacent fluid passageways wider at the opening than at the bottom so they are generally self-cleaning.

in principal, it is necessary to keep the width of the solid metal portions 30 small enough that, for a typical flow of coolant through the passageways 16, each portion 30 will be cooled to a temperature below that at which it will tend to burn out. At the same time, the temperature must be maintained high enough to conduct substantial heat to the cold face and create the counteracting force that diminishes or prevents the thermal warping of the panel.

By way of example only, a satisfactory panel of the above construction has dimensions of about 33 inches in width by 21 feet in length; a thickness from hot face side to cold face side of 2% inches and corrugations at 5 inch intervals across the width. The solid or dry portions 30 of the panel are 1 /2 inch in width and the strips 34 are 3%; inches wide. A suitable material is low carbon steel plate A or inch thick. A somewhat greater width of the solid metal portion 30 can be provided to establish a greater counteracting force to the hot face expansion that tends to bow the panel concave outward. For example, the width of the solid metal portions 30 can be increased to 2% inches in width, while decreasing the width of the strips 34 to approximately 2% inches. At the same time, the thickness of the panel from hot face side to cold face side should be increased in depth to approximately 2% inches so that a comparable flow of cooling fluid can be maintained. By way of example, coolant is circulated through the panel at a flow velocity of about 3 to 8 feet per second. Generally, the higher velocities are preferred.

While a preferred embodiment of this invention has been described in detail, it will be apparent that various modifications or alterations may be made therein without departing from the spirit and scope of the invention set forth in the appended claims.

What is claimed is:

1. A fluid-cooled metal hood panel for a basic oxygen furnace, said panel comprising two spaced headers, a plurality of parallel tubular fluid conduits extending between and connected at opposite ends to and in fluid communication with said headers, nonconduit-forming panel portions between and connecting adjacent fluid conduits, narrower than the conduits and offset to one side of a plane passing midway through and lengthwise of said conduits, said fluid conduits and nonconduitforming panel portions being formed of a corrugated sheet member having alternate ridges and valleys on each side and flat conduit-forming means spanning said valleys on one side only of said sheet member and comprised of a plurality of strips each welded between two adjacent ridges of said corrugated sheet member, and means for supplying fluid to one of said headers and exhausting fluid from the other.

2. A hood for a basic oxygen furnace or the like for collecting nd conducting hot gases, said hood comprised of panels that have a first surface facing inwardly of the hood and subjected to the direct heat of hot furnace gases and a second surface facing outwardly of the hood toward ambient atmosphere, said panels having (a) a plurality of tubular fluid conduits, (b) nonconduit-forming panel portions between and connecting adjacent fluid conduits, offset to the outward side of the hood from a plane passing midway. through and lengthwise of said conduits, and (0) means for supplying fluid to and exhausting fluid from said conduits, the said fluid conduits and nonconduit-forming panel portions being formed of corrugated sheet members having alternate ridges and valleys on each side and a plurality of strips spanning said valleys on only the side of said sheet members that face outwardly of the hood, each strip being welded between two adjacent ridges of said corrugated sheet members.

3. A fluid-cooled metal panel for a furnace hood, speciflcally adapted to have a first of two oppositely facing sides face a hot environment and the second side face a cooler, ambient, environment, said panel comprising a corrugated sheet member having alternate ridges and valleys on each side and a plurality of strips each welded between two adjacent ridges of the corrugated sheet member on one side only thereof to form tubular fluid conduits and said second panel side, nonconduitforming panel portions being between and structurally connecting adjacent fluid conduits, offset to the second side of the panel from a plane passing midway through and lengthwise of said conduits, the thickness of walls forming said conduits and nonconduit-forming panel portionsbeing substantially the same, and ports in said second side for supplying fluid to and exhausting fluid from said conduits.

4. A fluid-cooled metal panel for a furnace hood, specifically adapted to have a first of two oppositely facing sides face a hot environment and the second side face a cooler, ambient, environment, said panel comprising a plurality of spaced tubular fluid conduits, nonconduit-forming panel portions between and structurally connecting adjacent fluid conduits, and ports in said second side for supplying fluid to and exhausting fluid from said conduits, said fluid conduits and nonconduitforming panel portions being formed of a corrugated sheet member having alternate ridges and valleys on each side and fiat conduit-forming means between said ridges and spanning said valleys on one side only of said sheet member and secured thereto offset to the second side of the panel from a plane passing midway through and lengthwise of said ridges and valleys and in part forming the second panel side, the thickness of the sheet member and flat conduit-forming means being substantially the same so that the thickness of walls forming the conduits is substantially the same as the thickness of the nonconduit-forming panel portions. 

1. A fluid-cooled metal hood panel for a basic oxygen furnace, said panel comprising two spaced headers, a plurality of parallel tubular fluid conduits extending between and connected at opposite ends to and in fluid communication with said headers, nonconduit-forming panel portions between and connecting adjacent fluid conduits, narrower than the conduits and offset to one side of a plane passing midway through and lengthwise of said conduits, said fluid conduits and nonconduit-forming panel portions being formed of a corrugated sheet member having alternate ridges and valleys on each side and flat conduitforming means spanning said valleys on one side only of said sheet member and comprised of a plurality of strips each welded between two adjacent ridges of said corrugated sheet member, and means for supplying fluid to one of said headers and exhausting fluid from the other.
 2. A hood for a basic oxygen furnace or the like for collecting nd conducting hot gases, said hood comprised of panels that have a first surface facing inwardly of the hood and subjected to the direct heat of hot furnace gases and a second surface facing outwardly of the hood toward ambient atmosphere, said panels having (a) a plurality of tubular fluid conduits, (b) nonconduit-forming panel portions between and connecting adjacent fluid conduits, offset to the outward side of the hood from a plane passing midway through and lengthwise of said conduits, and (c) means for supplying fluid to and exhausting fluid from said conduits, the said fluid conduits and nonconduit-forming panel portions being formed of corrugated sheet members having alternate ridges and valleys on each side and a plurality of strips spanning said valleys on only the side of said sheet members that face outwardly of the hood, each strip being welded between two adjacent ridges of said corrugated sheet members.
 3. A fluid-cooled metal panel for a furnace hood, specifically adapted to have a first of two oppositely facing sides face a hot environment and the second side face a cooler, ambient, environment, said panel comprising a corrugated sheet member having alternate ridges and valleys on each side and a plurality of strips each welded between two adjacent ridges of the corrugated sheet member on one side only thereof to form tubular fluid conduits and said second panel side, nonconduit-forming panel portions being between and structurally connecting adjacent fluid conduits, offset to the second side of the panel from a plane passing midway through and lengthwise of said conduits, the thickness of walls forming said conduits and nonconduit-forming panel portions being substantially the same, and ports in said second side for supplying fluid to and exhausting fluid from said conduits.
 4. A fluid-cooled metal panel for a furnace hood, specifically adapted to have a first of two oppositely facing sides face a hot environment and the second side face a cooler, ambient, environment, said panel comprising a plurality of spaced tubular fluid conduits, nonconduit-forming panel portions between and structurally connecting adjacent fluid conduits, and ports in said second side for supplying fluid to and exhausting fluid from said conduits, said fluid conduits and nonconduit-forming panel portions being formed of a corrugated sheet member having alternate ridges and valleys on each side and flat conduit-forming means between said ridges and spanning said valleys on one side only of said sheet member and secured thereto offset to the second side of the panel from a plane passing midway through and lengthwise of said ridges and valleys and in part forming the second panel side, the thickness oF the sheet member and flat conduit-forming means being substantially the same so that the thickness of walls forming the conduits is substantially the same as the thickness of the nonconduit-forming panel portions. 